Reflective Arrayed Waveguide Grating

A photonic integrated circuit (PIC) for demultiplexing a multiplexed optical signal in to its constituent wavelengths and for combining n input optical signals composed of n different wavelengths in to a multiplexed signal. The said PIC is composed of:

• a plurality of input/output waveguides for inputting signal to and outputting signal from the PIC;
• a slab waveguide for coupling the input signal to the array of waveguides and for focusing the demultiplexed signals to the output waveguides;
• an array waveguide, containing plurality of waveguides which are optically coupled on the slab plane at one end, and terminated by a reflecting mirror on the other end, having a fixed path difference between neighboring waveguides, for coupling the input signal and then separate the same into constituent wavelengths and then focusing the individual wavelengths back on to the slab-input/output waveguide interface;
• a reflective mirror terminating the said array of waveguide for reflecting the signals incident on it from the array waveguide back into the array;
• and
• a substrate on which the input/output waveguides, the slab, and the array of waveguides are fabricated by a layer by layer approach. The assembly forms a photonic integrated circuit or an optical chip, termed as a reflective arrayed waveguide grating (RAWG).